数学j求教

13. 78% student was graduated from the school in 1980. 89% students graduated from the school in 1980. 问满足两个条件的学生比例。

这种题目的经典解释是：肉包子中a%是有摺的，有摺包子中b%是肉包子，实际上隐含的关系就是肉包子有摺的=有摺的肉包子，都是同一批包子（1980年毕业生的数目是一样的）..忘记是哪位NN在哪个月提出来的..肉包子同样出现在19

变体题目（或者说本身就是原题）：The sentence "students was graduated from high school" is accepted by 89% of the students, and the sentence   ''students graduated from high school '' is accepted by 78% of the students. 问两个同时被accept的概率。70%

我咋看不懂题目是啥意思捏？太弱了，惭愧，那位兄台给解释下啊。bow

同问 我也没有看懂